The present invention relates generally to bicycles, and more specifically to motor-driven electric bicycles.
Bicycles commonly have a main frame and a front fork pivotally secured to the main frame. The main frame typically includes a top tube, a down tube, a seat tube, and a rear wheel mount for receiving a rear wheel axle. The front fork typically includes a front wheel mount for receiving a front wheel axle. Steering control of the bicycle is provided by a handlebar that is usually secured to the front fork via a handlebar stem.
Some bicycles also include a hub motor that is mounted to the rear axle to assist with propelling the bicycle. In existing motor-driven electric bicycles, torque from the motor is transferred to the frame. Often, the torque exceeds the clamping forces on the rear axle, which causes the axle to spin freely relative to the frame. In some instances, a torque arm is externally bolted to the frame using a special connector and is further coupled to the axle to prevent axle rotation. Existing torque arms are prone to failure, and when they do fail, wires connected to the motor can become tangled and/or destroyed, potentially injuring the rider.